In the absence of extracellular Ca⁺⁺,an action potential in a motor neuron fails to initiate contraction of the innervated skeletal muscle because of:

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Quizplus · Accepted Answer

In the absence of extracellular calcium ions (Ca2+), the action potential in a motor neuron fails to initiate contraction of the innervated skeletal muscle primarily because calcium ions are essential for the release of neurotransmitters (such as acetylcholine, ACh) from the presynaptic terminal of the motor neuron. Without Ca2+ influx into the presynaptic terminal, the vesicles containing ACh cannot fuse with the presynaptic membrane to release ACh into the synaptic cleft, thereby inhibiting the initiation of muscle contraction.

In the Absence of Extracellular Ca++,an Action Potential in a Motor

In the Absence of Extracellular Ca⁺⁺,an Action Potential in a Motor